Corrected entry: In the scene where General Casey greets the Martians, and the Army is surrounding the event, they have Soviet T-55 tanks painted with American Markings.
Corrected entry: Kessler says during the TV interview that the reason the Martians went undetected by the Mars probe is that the probe didn't investigate the very deep Martian canals. There are no canals on Mars - the appearance of lines on the surface was caused by the faults of early telescopes, extensively documented in the 19th century and extensively debunked in the 20th.
Corrected entry: When the Martians first come to earth, the ambassador speaks Martian and the computer translates it into: "Greetings. I am the Martian ambassador." But much later in the movie, when the martians are attacking Las Vegas, a Martian says the exact same thing as the ambassador, and the nearby computer translates it into:"Don't run. We are your friends."